Risk assessment and mitigation of water quality systems: recoverable and non-recoverable responses to failure

在自然和人工环境中维持水质目标可能会受到可观察到的事件或输入的影响，例如流量变化，以及那些不可观察的事件或输入，例如机械故障，以及我们对管理此类系统的因果关系的有限理解。 输入在本质上可以是固定的，具有随时间的恒定平均值和标准偏差，或者是非固定的，表现出统计特性随时间的变化，例如，to climate气候change变化. 在任何情况下，预期水质对规划和运营决策的反应可能是相当可变的，未能达到水质目标可能是严重的，并且这种失败的后果可能是可以修复的，即，故障发生后，功能正常，或不可修复，不起作用。 不同领域为保护水质而采取的决策类型可能有所不同，但绩效目标是相似的，重点是尽可能可靠地达到水质标准。该项目开发分析技术，包括确定可靠性和其他性能措施，用于评估有关河流水质和供水系统的决策。 该项目将：1）在系统输入不稳定的情况下，推进可修复河流水质管理系统的性能测量的使用。 将制定和应用确定适应不断变化的投入条件的规划决策的方法; 2）制定和调查绩效措施的使用，以评估何时升级配水系统要素; 3）制定评估方法和实践方法，以提高水处理技术的可靠性，以实现健康目标。

Maintenance of water quality objectives in natural and constructed environments may be affected by events or inputs that are observable, such as variations in streamflow, and by those that are unobservable, such as mechanical failures, and by our limited understanding of the cause and effect relationships that govern such systems. The inputs may be stationary in nature, having a constant mean and standard deviation over time, or non-stationary, exhibiting changes in the statistical properties over time, due, e.g., to climate change. In any case, the expected water quality response to planning and operational decisions may be quite variable, failure to meet water quality objectives may be severe, and the consequences of such failures may be repairable, i.e., functioning, or non-repairable, not functioning, after failures occur. The types of decisions undertaken to protect water quality in different domains may differ; however the performance objectives are similar and focus on achieving water quality standards as reliably as possible. This project develops analytical techniques, including identification of reliability and other performance measures, for evaluating decisions regarding river water quality and water supply systems. This project will: 1) advance the use of performance measures for repairable river water quality management systems in cases where the system inputs are non-stationary. Methods for identifying planning decisions that adapt to changing input conditions will be developed and applied; 2) Develop and investigate the use of performance measures for evaluating when to upgrade water distribution system elements; and 3) Develop methods for estimating and practices for enhancing the reliability of water treatment technologies for meeting health targets.